Eliminating rancidity of glyceridic oils



United States Patcflii G F ELIMINATING RANCIDITY OF GLYCERIDIC OILS Louis Lang and Ronald J. Baird, Philadelphia, Pa., as-

signors to The National Sugar Refining Company, New York, N. Y., a corporation of New Jersey N Drawing. Application April 28, 1955 Serial No. 504,686

6 Claims. (Cl. 260-427) This invention is that of a method of removing rancidity from liquid glyceride oils. These include those that are liquid at atmospheric temperature as well as those that can be liquefied at elevated temperature at atmospheric pressure or at slight subatmospheric pressure, and without significant decomposition.

The expression liquid glyceride oils while including generically both the atmospheric temperature liquid, and the liquefiable, types just mentioned, also embraces both those of vegetable, as well as of animal, origin, and also compatible mixtures of any of them.

The method of the invention involves contacting such a liquid glyceride oil with a quantity of an alkali metal or alkaline earth metal sucrate, starchate, or cellulosate or mixtures of any of them suificient to remove the rancidity of the oil, and for a time suflicient to do so.

The method of the invention is applicable to remove the oxidative type, as well as the hydrolytic type, of rancidity of the various kinds of liquid glyceride oils.

These glyceride oils include, for example, vegetable oils such as cocoanut, corn, cottonseed, linseed, peanut, rapeseed, soyabean oils, and others; and animal oils whether of marine animals origin such as the fish oils and whale oils and the cod, shark, and whale liver oils, or of land animal origin as tallow and even butter.

The reduction or elimination of rancidity in liquid gylceride oils, by the methods available prior to the invention, involved a number of steps that made the procedures relatively costly. In some cases expensive distillations, under vacuum or with steam, or both are involved. In others, treatment with various chemicals and bleaching operations are included, necessitating also aqueous washing and the problem of adequate drying. The latter still entails the problem of residual Water and thus the possibility of hydrolytic rancidity again.

These and other problems and disadvantages are avoided by the simple procedure involved in the method of the invention. According to it, a rancid glyceride oil, having either or both types of rancidity, need only be contacted with the free-flowing alkali metal or alkaline earth metal sucrate, starchate or cellulosate, or mixture of them, and in a quantity sufiicient substantially to eliminate the rancidity and for a time suflicient to do so.

That is done very readily by the method of the invention merely by uniformly distributing a comparatively small amount of such metal derivative of the polysaccharide by shaking or stirring in the liquid glyceride oil, or by passing the oil through a bed of the sucrate, starchate or cellulosate, and advantageously at an elevated temperature below that at which significant decomposi tion of the oil can occur.

The amount of any particular sucrate, starchate, or cellulosate to be used will depend always on the nature and extent of the rancidity of the specific oil to be treated (i. e. sweetened). It will regularly be a small amount relative to the oil. Merely as a relatively general indication, it might not often be as much as about five percent, and quite generally might be found to be under A 2,827,472 Patented Mar. 18, 1958 about two percent, and quite often could be found more likely to be some part of one percent. Then quite commonly, it could be about one-tenth of one percent, and even less than that. A lower limit cannot be indicated because for the slightest rancidity there would be required possibly merely a minute amount of the treating substance. A slight excess can do no harm. The specific amount required can be indicated readily by the simple test of taking a small sample of the particular oil to be treated and shaking it, preferably at elevated temperature, with one-tenth percent of the selected alkali, or alkaline earth, metal salt of the polysaccharide (namely, the alkali, or alkaline earth, metal sucrate, starchate or cellulosate). Part of the sample then can be filtered and smelled and/or tasted to tell whether or not the rancidity has been eliminated. If it has, the ratio of the sucrate, starchate or cellulosate is adequate. This test can be repeated with a slightly smaller proportion. If the small filtered part of the treated sample should still smell or taste rancid, a slightly further amount should be added and the test continued as described to obtain an indication of the suflicient proportion.

The invention is illustrated by, but not restricted to, the following examples:

Example 1-0xidative rancidity: To one hundred pounds of linseed oil having oxidative rancidity, in an open vessel equipped with agitator, there was added onetenth pound of disodium sucrate (obtained by reacting sodium ethoxide with a solution of sucrose in an amine as in Ronald J. Baird U. S. Patent No. 2,702,249, issued February 15, 1955). The mixture was heated and stirred and held within one hundred twenty-five to one hundred thirty degrees Fahrenheit for one-half hour, and then filtered. The filtrate, treated (sweetened) oil was somewhat lighter in color than the original oil (before treatment) and no longer exhibited any rancid odor and taste.

Example 2Oxidative and hydrolytic rancidities: To one hundred pounds of coconut oil having both oxidative and hydrolytic rancidity, in an open vessel equipped with agitator, there was added two-tenths pound of sodium cellulosate (free-running particles called crumbs, in the field). The mixture was heated and stirred and held within one hundred and twenty-five to one hundred thirty degrees Fahrenheit for one-half hour, and then filtered. The filtered, treated (sweetened) oil was somewhat lighter in color than the original oil (before treatment) and no longer exhibited rancid odor and taste.

The disodium sucrate used in Example 1 can be replaced by disodium sucrate obtained by any other method. Likewise, the disodium sucrate and the sodium cellulosate of these examples can be replaced, in whole or in part, by the equivalent amount of any other alkali metal, as potassium or lithium, or alkaline earth metal, as calcium, barium, strontium or magnesium, sucrate, starchate or cellulosate, or mixtures of any of these. As seen from Baird Patent 2,702,249, the salt of the polysaccharide is the non-carboxylate type.

The linseed oil of Example 1 can be replaced by any other glyceride oil having oxidative rancidity and of vegetable or animal origin. So also, the coconut oil of Example 2 can be replaced by any other glyceride oil having both oxidative and hydrolytic rancidity and also of vegetable or animal origin.

In some operations, it may be found convenient to make the contact between the oil and the rancidity-removing agent by percolating the oil, preferably at elevated temperature, through a bed, of suitable size and depth of the selected rancidity-removing agent of the invention, to enable sufiicient time of contact between the oil and the rancidity-removing agent to remove the rancidity. if desired, the bed can be made of considerable depth to be able to handle a relatively extensive volume of the assure rancid oil to be treated. Insome such case, it can be advantageous to have the vessel holding the bed of the agent jacketted to permit controlled heating.

7 In any event the invention is not foun-dedinteaching any particular range of proportions betvyeeni the rancid! ity-removing agent'andthe rancid;oi.l fto be ,SWeetenedi or in-th'e rate of flow or the oil"percolated through a bed of the agent or in theparticular depth of thejbed.

The fundamental featureof the invention is the disco jvery that these alkali, or alkaline earth, metal sucrates,'s tarchates or cellulosates, or mixtures ofia'ny of them, are effective toremove the indicated rancidity fromthe glyeeride oils, and by so simplea procedure; 1 a f a "While the invention: has been illustrated by detailed description of certain specific embodimentso'f it, it is understood that various modificationsand substitutions can be made in various features of'any ofthem within the scope of the appended claims which areintendedialso to embrace 1 equivalents of, the .various tembodiments.

What is claimed is:

1. The method of eliminating rancidity of'a glyceride oil, which method comprises contacting the rancid glyceride oil with a quantity of a rancidity-removing agent from the class consisting of an alkali metal sucrate, an

alkaline earth metal sucrate, and alkali metal starchate,,

an alkaline earth metal starchate, an alkali metal cellulosate, an alkaline earth cellulosate, and a mixture of any of them, sufficient to eliminate the rancidity and for a time sufficient to do so; and separating the rancidityremoving agent from the thus treated oil.

2. The method as claimed in claim 1, wherein the rancidity-removing agent is added to the rancid oil and the'resulting mixture is agitated.

3. The method as claimed in claim 2, wherein the mixture is heated while the rancidity-removing agent is in contact with the oil and at a temperature below that at which decomposition of the oil occurs, and when the contact has continued long enough for the rancidity to be re raved, filtering the mixture to remove the agent.

4. The method as cla med in claim 3, wherein the temperature to which the mixture is heated does not exceed one hundred and sixty degrees Fahrenheit. 7

5. The method as claimed in claim 1, wherein the quantity of the rancidity-removing agent is under about five percent by Weight of the rancid oil.

6. Themethod as Claimed in claim 4, quantity of the rancidity-removing agent is one percent of the rancid oil. I

wherein the under about References Cited in'the file of this patent UNITED STATES PATENTS 636,860 Sickels Nov. 14, 1899 1,246,379 Baskerville Nov. 13, 1917 2,272,964 Coe et al Feb. 10, 1942 

1. THE METHOD OF ELIMINATING RANCIDITY OF A GLYCERIDE OIL, WHICH METHOD COMPRISES CONTACTING THE RANCID GLYCERIDE OIL WITH A QUANTITY OF A RANCIDITY-REMOVING AGENT FROM THE CLASS CONSISTING OF AN ALKALI METAL SUCRATE, AN ALKALINE EARTH METAL SUCRATE, AND ALKALI METAL STARCHATE, AN ALKALINE EARTH METAL STARCHATE, AN ALKALI METAL CELLULOSATE, AN ALKALINE EARTH CELLULOSATE, AND A MIXTURE OF ANY OF THEM, SUFFICIENT TO ELIMINATE THE RANCIDITY AND FOR A TIME SUFFICIENT TO DO SO; AND SEPARATING THE RANCIDITYREMOVING AGENT FROM THE THUS TREATED OIL. 